The conventional T8 fluorescent lighting tube having a diameter about 28 mm is large in volume to adversely occupy a relatively large space, and has low brightness, short service life, and high power consumption, compared to the newly developed T5 fluorescent lighting tube having a diameter about 16 mm, and is therefore gradually replaced by the improved T5 lighting tube.
Please refer to FIG. 1. The conventional T8 lighting tube 8 has a relatively large diameter, and a distance between two tube pins 81 spaced on each end of the lighting tube 8 is relatively large, accordingly. Herein, the distance between the two tube pins 81 is defined as the first distance D. Meanwhile, a socket 9 corresponding to the lighting tube 8 is provided with two pin insertion holes 91 for receiving the two tube pins 81. Therefore, a distance between the two pin insertion holes 91 must be the same as the first distance D.
However, the newly developed T5 fluorescent lighting tube has a relatively small diameter, and the distance between two tube pins spaced on each end thereof is relatively small, too. Herein, the distance between the two tube pins of the T5 lighting tube is defined as the second distance d, as shown in FIG. 4. The second distance d is obviously different from and smaller than the first distance D. Therefore, the T5 lighting tube and the socket 9 intended for the T8 lighting tube could not match each other. In other words, the existing T5 lighting tube could not be directly assembled to the socket 9 having a T8 specification. If it is desired to use the T5 lighting tube that provides improved lighting effect, the socket 9 must be changed to another socket having a T5 specification. For this purpose, a new mold must be made for producing the socket matching the T5 lighting tube. In addition, a steel holder 92 of the lighting tube for holding the socket 9 must also be changed at the same time. Such replacement involves in a lot of time, labor, and material to largely increase the cost for installing the T5 lighting tube.
It is therefore desirable to develop a simple way to electrically connect the T5 lighting tube with better lighting performance to the existing socket with T8 specification, so that the socket with T8 specification has widened applicability and the cost for installing new T5 lighting tubes can be reduced.